st: RE: Splitting string variables "advanced"

[Nick Cox <n.j.cox@durham.ac.uk>]

This is a bit of a kludge but the technique may help. (I tried regex approaches including -moss- (SSC) without success, but there may well be a better solution that way.) 

gen copy = itrim(myvar) 

gen isnum = . 

local todo 1
 
quietly while `todo' { 
	replace isnum = !missing(real(substr(copy, strpos(copy, ";") + 4, 1))) 
	replace copy = subinstr(copy, ";", cond(isnum, "@", ","), 1) 
      count if strpos(copy, ";") 
      local todo = r(N) 
}

The logic of this is 

1. -itrim()- first. It shouldn't make anything more difficult, and it might help. 

2. "Number" for you evidently means something beginning something like "US2" or "EP1". So I look for a numeric character in a certain position. 

3. Depending on what is found, I replace ";" by "@" or ",". 

4. Later I would -split- on "@". Clearly you should use a character not otherwise present which you can check with -count if strpos(myvariable, "@")-. 

Nick 
n.j.cox@durham.ac.uk 

Seliger Florian

I want to split string variables with values such as:

EP1763200-A1 -- EP1530342-A2   ;  US2004199663-A1   HORVITZ E J (HORV-Individual);  APACIBLE J T (APAC-Individual)   HORVITZ E J,  APACIBLE J T;  US2004254998-A1   MICROSOFT CORP (MICT)   HORVITZ E J

 

At the end, there should be several variables and their values should look as follows:

 

Var1
EP1763200-A1 -- EP1530342-A2   

Var2
US2004199663-A1   HORVITZ E J (HORV-Individual);  APACIBLE J T (APAC-Individual)   HORVITZ E J,  APACIBLE J T

Var3
US2004254998-A1   MICROSOFT CORP (MICT)   HORVITZ E J

 

My problem is the following: I used 

split cp, p(" ; " "; ")

but in this case, Stata will also split Var2 because of the semicolon.

I'm searching for a way to tell Stata that it should keep the value of Var2 in one variable if there is a semicolon before a name.

Stata shall be asked to split the variable only if there is a number after the semicolon.

Alternatively, I would like to delete the confusing semicolon in a first step, then asking Stata to split the variable with split cp, p(" ; " "; ").


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